Module stream 

Stream-family trait methods on the Postgres backend (RFC-015).

This module houses the four stream methods called from EngineBackend on crate::PostgresBackend:

1. append_frame — Durable, DurableSummary (with JSON Merge Patch apply), and BestEffortLive (EMA-driven dynamic MAXLEN).
2. read_stream — XRANGE-equivalent over (ts_ms, seq).
3. tail_stream — blocking tail via the shared crate::listener::StreamNotifier; NO pg connection is held while parked (Q2).
4. read_summary — reads the rolling DurableSummary document.

Functions

append_frame

read_stream

read_summary

tail_stream